The invention relates to a device for the anaerobic fermentation of organic waste material such as manure in a substantially liquid condition.
For the anaerobic fermentation of organic waste material such as liquid manure it is necessary to transfer this material first of all into more simple and soluble compositions by acidification, which compositions are suitable to be fermented by methane bacteria while generating methane and carbon dioxide gas (biogas). In particular when the waste material comprises solid organic components, a hydrolysis is first of all necessary, which transfers such components into soluble substances. Hydrolysis and acidification may take place in the same space mainly by the same types of bacteria.
For smaller plants, for instance on farms, experiments have been made with biogas devices which were relatively expensive to obtain such fermentation. Such devices have several objections, both as to the costs as to the maintaining of the process in an active state and therein hydrolysis and acidification often took place in the same space as the methane fermentation, although this has disadvantages for an efficient performance of the several processes, the yield of biogas was relatively small and a relatively considerable part of said gas was necessary for the energy required by the device itself for pumping, mixing and stirring.